Atmospheric Chemistry and Physics (Apr 2016)
Aerosol optical properties in the southeastern United States in summer – Part 1: Hygroscopic growth
- C. A. Brock,
- N. L. Wagner,
- N. L. Wagner,
- B. E. Anderson,
- A. R. Attwood,
- A. R. Attwood,
- A. R. Attwood,
- A. Beyersdorf,
- P. Campuzano-Jost,
- P. Campuzano-Jost,
- A. G. Carlton,
- D. A. Day,
- D. A. Day,
- G. S. Diskin,
- T. D. Gordon,
- T. D. Gordon,
- T. D. Gordon,
- J. L. Jimenez,
- J. L. Jimenez,
- D. A. Lack,
- D. A. Lack,
- D. A. Lack,
- J. Liao,
- J. Liao,
- J. Liao,
- M. Z. Markovic,
- M. Z. Markovic,
- M. Z. Markovic,
- A. M. Middlebrook,
- N. L. Ng,
- N. L. Ng,
- A. E. Perring,
- A. E. Perring,
- M. S. Richardson,
- M. S. Richardson,
- J. P. Schwarz,
- R. A. Washenfelder,
- R. A. Washenfelder,
- A. Welti,
- A. Welti,
- A. Welti,
- L. Xu,
- L. D. Ziemba,
- D. M. Murphy
Affiliations
- C. A. Brock
- NOAA Earth System Research Laboratory, Boulder, Colorado, USA
- N. L. Wagner
- NOAA Earth System Research Laboratory, Boulder, Colorado, USA
- N. L. Wagner
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado, USA
- B. E. Anderson
- NASA Langley Research Center, Hampton, Virginia, USA
- A. R. Attwood
- NOAA Earth System Research Laboratory, Boulder, Colorado, USA
- A. R. Attwood
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado, USA
- A. R. Attwood
- now at: Droplet Measurement Technologies, Boulder, Colorado, USA
- A. Beyersdorf
- NASA Langley Research Center, Hampton, Virginia, USA
- P. Campuzano-Jost
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado, USA
- P. Campuzano-Jost
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado, USA
- A. G. Carlton
- Department of Environmental Sciences, Rutgers University, New Brunswick, New Jersey, USA
- D. A. Day
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado, USA
- D. A. Day
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado, USA
- G. S. Diskin
- NASA Langley Research Center, Hampton, Virginia, USA
- T. D. Gordon
- NOAA Earth System Research Laboratory, Boulder, Colorado, USA
- T. D. Gordon
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado, USA
- T. D. Gordon
- now at: Handix Scientific, Boulder, Colorado, USA
- J. L. Jimenez
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado, USA
- J. L. Jimenez
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado, USA
- D. A. Lack
- NOAA Earth System Research Laboratory, Boulder, Colorado, USA
- D. A. Lack
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado, USA
- D. A. Lack
- now at: TEAC Consulting, Brisbane, Australia
- J. Liao
- NOAA Earth System Research Laboratory, Boulder, Colorado, USA
- J. Liao
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado, USA
- J. Liao
- now at: NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
- M. Z. Markovic
- NOAA Earth System Research Laboratory, Boulder, Colorado, USA
- M. Z. Markovic
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado, USA
- M. Z. Markovic
- now at: Air Quality Research Division, Environment Canada, Toronto, Ontario, Canada
- A. M. Middlebrook
- NOAA Earth System Research Laboratory, Boulder, Colorado, USA
- N. L. Ng
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
- N. L. Ng
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA
- A. E. Perring
- NOAA Earth System Research Laboratory, Boulder, Colorado, USA
- A. E. Perring
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado, USA
- M. S. Richardson
- NOAA Earth System Research Laboratory, Boulder, Colorado, USA
- M. S. Richardson
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado, USA
- J. P. Schwarz
- NOAA Earth System Research Laboratory, Boulder, Colorado, USA
- R. A. Washenfelder
- NOAA Earth System Research Laboratory, Boulder, Colorado, USA
- R. A. Washenfelder
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado, USA
- A. Welti
- NOAA Earth System Research Laboratory, Boulder, Colorado, USA
- A. Welti
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado, USA
- A. Welti
- now at: Department of Physics, Leibniz Institute for Tropospheric Research, Leipzig, Germany
- L. Xu
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA
- L. D. Ziemba
- NASA Langley Research Center, Hampton, Virginia, USA
- D. M. Murphy
- NOAA Earth System Research Laboratory, Boulder, Colorado, USA
- DOI
- https://doi.org/10.5194/acp-16-4987-2016
- Journal volume & issue
-
Vol. 16
pp. 4987 – 5007
Abstract
Aircraft observations of meteorological, trace gas, and aerosol properties were made during May–September 2013 in the southeastern United States (US) under fair-weather, afternoon conditions with well-defined planetary boundary layer structure. Optical extinction at 532 nm was directly measured at relative humidities (RHs) of ∼ 15, ∼ 70, and ∼ 90 % and compared with extinction calculated from measurements of aerosol composition and size distribution using the κ-Köhler approximation for hygroscopic growth. The calculated enhancement in hydrated aerosol extinction with relative humidity, f(RH), calculated by this method agreed well with the observed f(RH) at ∼ 90 % RH. The dominance of organic aerosol, which comprised 65 ± 10 % of particulate matter with aerodynamic diameter < 1 µm in the planetary boundary layer, resulted in relatively low f(RH) values of 1.43 ± 0.67 at 70 % RH and 2.28 ± 1.05 at 90 % RH. The subsaturated κ-Köhler hygroscopicity parameter κ for the organic fraction of the aerosol must have been < 0.10 to be consistent with 75 % of the observations within uncertainties, with a best estimate of κ = 0.05. This subsaturated κ value for the organic aerosol in the southeastern US is broadly consistent with field studies in rural environments. A new, physically based, single-parameter representation was developed that better described f(RH) than did the widely used gamma power-law approximation.
